The prior-art pivoting transfer means of belt conveyors for bulk material are usually designed as follows:
The bulk material arriving from a first belt conveyor is thrown against a baffle plate, which is arranged at a short distance behind the vertical pivot axis. As a result, the horizontal velocity component of the bulk material is reduced to zero over the shortest possible distance. As a consequence of the force of gravity, the bulk material is accelerated in the downward direction, and the bulk material at the same time obtains a small horizontal velocity component against the original direction of delivery due to the rebound force as well as to fluidic effects.
The baffle plate is arranged such that the downwardly directed jet of bulk material will arrive as accurately as possible in the vertical pivot axis of the second belt conveyor. The vertical velocity component is again reduced to zero over the shortest possible distance there. The bulk material is then again accelerated by its own weight and by friction in the direction of delivery of the second belt conveyor, until it reaches the velocity of the second belt conveyor after a certain acceleration section (on the order of magnitude of 1 to 5 m).
To guide the bulk material, chutes are arranged in the area of the belt conveyor, besides the baffle plate.
The disadvantage of this design is the fact that large amounts of energy are inherently continuously destroyed by friction and converted into heat in the area of the pivoting transfer means. The baffle plate, the chutes and the rubber belt of the second belt conveyor are subject to intense wear. Therefore, they require frequent maintenance and replacement, or they must be frequently equipped with new wear material. The lost energy must continuously be applied by the belt drives.
Since the force of gravity is utilized between the first and second belt conveyors, the direction of delivery must always be from the discharge end of the first belt conveyor, which discharge end is arranged at a higher level, to the second belt conveyor. Consequently, the direction of delivery cannot be reversed, unless the height positions of the belts are reversed.
Pivoting transfer means are defined as means in which the second belt conveyor is arranged pivotably around a vertical axis in relation to the first belt conveyor, or in which the direction of delivery of the second belt conveyor is or can be different from that of the first belt conveyor from a bird's eye view.